Guys
Very new to this.
I am trying to first use the tool to find PDF files equal to or above 150MB. I use the following command switchs
exiftool.exe -filesize -if "$filesize ge 150" "split_merged*.pdf"
Have I the correct syntax for tags with numerical values?
The problem is that you are using a string comparison (ge) which doesn't work the same way as a numeric comparison. Also, the FileSize tag lists the size as KB/MB/GB/etc. So a file that was "150 KB" would return as true.
What you need to do is a numeric comparison of the raw byte size. This is done using the hashtag # shortcut of the -n (--printConv) option (https://exiftool.org/exiftool_pod.html#n---printConv). The -fast4 option (https://exiftool.org/exiftool_pod.html#fast-NUM) is used to avoid decoding all the embedded metadata and only look at the file system metadata.
exiftool -fast4 -filesize -if "$filesize#>150000000" "split_merged*.pdf"
Having said that, exiftool will still be pretty slow compared to other options. If you are on Mac/Linux, then the find command will be significantly faster.
Windows, unfortunately, doesn't have an easy built-in solution. This SuperUser answer (https://superuser.com/questions/64481/) has a few ways to do it.
The best solution for Windows, IMO, is VoidTools Everything Search (https://www.voidtools.com/). Everything indexes all the files on your system using properties of the NTFS so it is insanely fast. Through the GUI, you would set the search as
c:\path\to\PDFs ext:pdf size:>150mb
There's also a command line tool you would install separately. And it uses the same syntax, so on the command line you would type
es c:\path\to\PDFs ext:pdf size:>150mb
Thank you for the prompt, clear answer and options. Plenty to explore.